1. Field of the Invention
The present invention generally relates to characterization of color devices and more particularly to correction of a color input device's forward model.
2. Description of the Related Art
In order to mimic the human visual system, color input devices used to sense colors represent colors using three colors of light, namely Red, Green, and Blue (RGB). By measuring varying intensities of these three colors of light, color input devices can simulate the human perception of a variety of colors. For example, a color input device, such as a document scanner, uses light sensors to measure the intensity of red, green, and blue light reflected from an object. The light intensities are then used to represent colors as RGB color values in the color input device's own device dependent RGB color space.
A forward model maps RGB color values received from the color input device into a device independent color space. This allows use of a color input device's color values by other color devices through the use of a common Color Management Module (CMM). A possible problem with forward models of input devices is that the output of the model may not always be physically meaningful, i.e., they might not define colors that lie within the human visual gamut as determined by the CIE. The cause of this is the fact that the building blocks of the model, such as monomials or other basis functions, are general mathematical objects and not particularly color science savvy. As such, the values they produce are not constrained to represent colors that are visible to the human observer. This problem may become exacerbated when the forward model is used to extrapolate colors for RGB values not in the original training sampled data.
Therefore, a need exists for a method to ensure a forward model for a color device generates physically meaningful color values. Various aspects of the present invention meet such a need.